Characterization of dissolved organic matter in a dynamic membrane bioreactor for wastewater treatment

This paper systematically examined the characteristics of dissolved organic matter (DOM) in a dynamic membrane bioreactor (DMBR) for municipal wastewater with a laboratory-scale continuous-flow device. Experimental results showed that the system performed excellent pollutants' removal efficiencies. The increase of trans-membrane pressure (TMP) for the dynamic membrane (DM) could be divided into three stages, i.e., zero increase stage, slow increase stage and abrupt rise stage. The maximal fouling rate of the DM reached to 4.34 kPa/h in abrupt rise stage. It was observed that the polysaccharides (PS) concentration of DOM samples gradually increased from the anaerobic zone to the aerobic zone in sequence, but the proteins (PN) concentration performed an opposite trend. The DM could retain a small part of the large molecular substances (>10 kDa) in the aerobic zone. Two particular fluorescence peaks appeared in the anaerobic zone and in the anoxic zone were also found in the effluent, which illustrated the dynamic cake layer closed to the stainless steel mesh might induce an anaerobic/anoxic micro environment. Based on the three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy analysis, aromatic proteins, aromatic protein-like substance, fulvic acid-like substances and soluble microbial by-product-like materials could be biodegraded effectively in the DMBR, and the DM could partly remove the humic acid-like substances and soluble microbial by-product-like materials.